The present disclosure relates to an image forming apparatus.
Conventionally, among image forming apparatuses such as printers, copy machines, and multifunction peripherals, there is a model on which a plurality of option devices (e.g., auxiliary sheet feed devices, etc.) for extending or adding functions are mountable. An apparatus main body of such an image forming apparatus includes a main body control portion which controls an image forming operation. Meanwhile, each option device includes an option control portion which is connected to the main body control portion in a communicable manner and controls an operation of the option device that is the self-device, on the basis of a control signal inputted from the main body control portion. For example, in the case where a plurality of auxiliary sheet feed devices are mounted as option devices on the apparatus main body, when initial communication is performed immediately after start of power supply, the main body control portion of the apparatus main body outputs a signal for causing each auxiliary sheet feed device to identify its mounted position (mounted stage number), via a selection signal line. Meanwhile, the option control portion of each auxiliary sheet feed device identifies the mounted position of the auxiliary sheet feed device that is the self-device, on the basis of the signal inputted from the apparatus main body.
For example, as conventional art, a printer is known which includes four stages of option trays (auxiliary sheet feed devices) and causes each option tray to identify its mounted position (mounted stage number) by using a left-rotate and carry mode. In the printer, a position designation signal output portion (corresponding to the above main body control portion) outputs, for example, a 2-bit position designation signal to the option tray in the uppermost stage. Upon reception of the position designation signal, an option position determination portion (corresponding to the above option control portion) of the option tray in the uppermost stage collates information regarding the mounted position of the option tray which is stored in an option position storage portion and corresponds to the value of the 2 bits, with the value of the 2 bits of the received position designation signal, and identifies the mounted position of the option tray that is the self-device. Furthermore, the option position determination portion inverts the high-order bit of the 2 bits of the position designation signal, interchanges the high-order bit with the low-order bit, and outputs the resultant signal to the option trays in the lower stages.